Late Cretaceous carbon isotope curves generated for localities in Europe, Asia, and the deep-sea records have provided the foundation for development of a contiguous, intercontinental chemostratigraphic framework. Despite the development of carbon isotope records from selected stratigraphic intervals in the Western Interior Basin, however, a comprehensive d 13 C record comparable to those developed in Europe and Asia, and from ODP sites, had not yet been completed. This study reports a new, high-resolution Cenomanian to Campanian carbon isotope record for the central Western Interior Basin of North America that makes a key contribution to the intercontinental correlation. The curve is correlated to the well-developed molluscan biostratigraphic framework for the Western Interior Basin, as well as a revised geochronology based on integration of new radioisotopic dating and astrochronology developed in the same core records from where the d 13 C data were derived. The new d 13 C record reflects not only major perturbations in the global carbon cycle, such as the midCenomanian Event and the Cenomanian-Turonian Ocean Anoxic Event 2, but also smaller excursions that have been recognized in records from Europe and Asia. This shows that the Western Interior shallow epeiric sea was not isolated for any appreciable part of Cenomanian to early Campanian time-it consistently recorded changes in the global marine carbon cycle observed elsewhere. A critical attribute of the chemostratigraphic dataset produced in this study is its linkage with a revised Late Cretaceous time scale. Assignment of revised ages to Western Interior carbon isotope events that are globally expressed will allow export of the improved time scale to localities within and outside the Western Interior where similar carbon isotope records have been generated. This chronostratigraphic tool will allow a number of stratigraphic and geochemical hypotheses to be more rigorously tested.

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Neodymium (Nd) isotopes in leached authigenic components of marine sediments have been increasingly used as a tracer of past ocean-water masses. Despite the general assumption that the Nd isotopic composition of solutes released during chemical weathering fingerprints the source rocks on continents, preferential dissolution of easily dissolvable phases may result in significant deviations in Nd isotopic composition between the solutes and the source rocks, with potential implications for the utility of Nd isotopes in paleoenvironmental studies. Here, we present the Nd isotopic compositions of leached and detrital fractions separated from bedrock and marine sediment samples from the Svalbard archipelago. Our goal is to further understand the behaviour of Nd isotopes during chemical weathering in glacial catchments and evaluate how glacier fluctuations and associated weathering congruency may have affected the export of dissolved Nd isotope signatures to seawater. Highlights► There are differences between detrital and leached εNd (△εNd) in Svalbard bedrock. ► The leached εNd are more radiogenic than detrital εNd in Svalbard fjord sediments. ► The △εNd are generally higher during the periods of glacier advances. ► Glacial incongruent weathering could cause higher △εNd. ► △εNd could be a tracer for glacial fluctuation and associated nutrient inputs.

Provenance and tectonic history of the Jurassic accretionary complex, Mino terrane, located in the Inner Zone of south-west Japan, were studied using sandstone framework composition and mudrock geochemistry. Modal analysis of sandstones shows that the tectonic setting of the source area for the studied Mino terrane clastic rocks was uplifted basement, largely dominated by highgrade metamorphic terrain composed of quartz and feldspar, especially plagioclase. The textural and mineralogical immaturity, extent of alkali and alkaline earth element leaching, low chemical index of alteration values and depleted rare earth element (REE) contents suggest rapid uplift and erosion within the source terrain and a relatively weak weathering intensity. Factor analysis revealed that grain-size effects governed compositional heterogeneity in the studied sediments. Provenance of the sediments is interpreted as being plagioclase-enriched felsic basement rock, such as granodiorite, within a continental margin and evolved arc tectonic setting rather than active volcanic arc. Lack of a contribution from active volcanic arcs may have resulted from the cessation of volcanism during the reorganization of the subducting plate system and/or erosion of arc volcanics and exposure of basement. Considering the previous studies on palaeogeography and palaeocurrent reconstruction, the north-eastern part of the Yeongnam massif in the Korean Peninsula is interpreted as the most probable source area for the studied turbidites. The results of mixing calculation for Mino terrane sediments suggest that Precambrian leucocratic granite and the basement rock of the Cretaceous Gyeongsang Basin shed large amounts of sediments to the Mino trench, whilst Precambrian granitic gneiss and the Triassic pluton supplied lesser amounts. The results of this study reveal that, although active subduction-accretion processes were occurring, the Mino trench was bordered by continental basement rocks. This knowledge contributes to enhanced understanding of the Jurassic palaeogeography of the east Asia continental margin.